System packages are always light but share the same dependencies with everything else which saves space. However, they don’t have any sandboxing, which makes them less secure than Flatpaks. It’s best to use those for simple programs.

Flatpaks are amazing because each Flatpak is sandboxed with its own dependencies, and if you already have the dependency on your device, it doesn’t download it again but clones it from your device to reduce bandwidth load. Flatpaks are a great fallback when system packages aren’t available because they’re compatible with all Linux distributions and I advise you use them primarily for any program that connects to the Internet as they’re more secure.

Snaps are worse Flatpaks lmao